20991300 has 72 divisors (see below), whose sum is σ = 66266592. Its totient is φ = 5088000.

The previous prime is 20991293. The next prime is 20991317. The reversal of 20991300 is 319902.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 120 + ... + 6480.

Almost surely, 2^20991300 is an apocalyptic number.

20991300 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20991300, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33133296).

20991300 is an abundant number, since it is smaller than the sum of its proper divisors (45275292).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20991300 is a wasteful number, since it uses less digits than its factorization.

20991300 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6389 (or 6382 counting only the distinct ones).

The product of its (nonzero) digits is 486, while the sum is 24.

The square root of 20991300 is about 4581.6263487980. The cubic root of 20991300 is about 275.8543129464.

The spelling of 20991300 in words is "twenty million, nine hundred ninety-one thousand, three hundred".